body {
    /* background: #f2f2f2; */
    background: #282c34;
}

.frame {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 400px;
    height: 400px;
    margin-top: -200px;
    margin-left: -200px;
    border-radius: 2px;
    box-shadow: 1px 2px 10px 0px rgba(0, 0, 0, 0.3);
}

.center {
    position: absolute;
    text-align: center;
    width: 400px;
    height: 400px;
    top: 0;
    left: 0;
    overflow: hidden;
}

input[type='radio'] {
    display: none;
}

.circle {
    box-sizing: border-box;
    position: absolute;
    z-index: 5;
    top: 175px;
    left: 115px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: 2px solid #fff;
    cursor: pointer;
}

#c2 {
    left: 175px;
}

#c3 {
    left: 235px;
}

.active {
    position: absolute;
    z-index: 10;
    width: 40px;
    height: 40px;
    background: #fff;
    border-radius: 50%;
    top: 180px;
    left: 120px;
    transition: all 1s ease;
}

#check-1:checked ~ .active {
    transform: translateX(0px);
}
#check-2:checked ~ .active {
    transform: translateX(60px);
}
#check-3:checked ~ .active {
    transform: translateX(120px);
}

.bg {
    position: absolute;
    width: 400px;
    height: 400px;
    top: 0;
    left: 0;
    background: #3498db;
    border-left: 400px solid #9b59b6;
    border-right: 400px solid #1abc9c;
    transform: translateX(0px);
    transition: all 1s ease;
}

#check-1:checked ~ .bg {
    transform: translateX(0px);
}
#check-2:checked ~ .bg {
    transform: translateX(-400px);
}
#check-3:checked ~ .bg {
    transform: translateX(-800px);
}
